Öz Background/aim: This study aimed to identify IDUA gene mutations in Turkish patients morphologically (phenotypic) diagnosed with MPS type I. It also sought to discuss the possible effects of detected mutations on alpha-L-iduronidase enzyme function based on current knowledge. Materials and methods: Genetic analysis was carried out in 15 patients using direct DNA sequencing. Moreover, segregation analysis was performed among family members to predict the pathogenic effect of novel mutations, and computational programs were used to predict their functional impact. Results: Nine different mutations (c.494-1G>A, c.793-6C>G, c.793-5C>A, p.M1L, p.Y64X, p.A327P, p.W402X, p.P533L, and p.R628X) were identified. Computational analysis results supported the pathogenicity of novel mutations, suggesting improper splicing. Seven already-known polymorphisms were detected in the screened cohort as well. Conclusion: Our results revealed heterogeneity in the mutation spectrum of Turkish patients. Six of the mutations, including the novel ones, have never before been reported in the Turkish population. Moreover, 5 patients who were phenotypically diagnosed with MPS type I could not be confirmed by genetic analysis, indicating the importance of the molecular characterization of MPS subtypes.